Rock flower anemone in 20gal?

[zum14]

So i have never been huge into anemones. There really neat, but just never had an urge to get one. That was untill i saw the flower anemone in Snappys tank. Really neat. So ive done some research on them, i think i have a few good areas one would like and people are clasifying them in the easy category but am curious if anyone thinks a 20 gal is too small for one? I will be getting a 150w pendant in the near future. Currently have no fish and am not planning anything too crazy with them. Thanks.